Binarity & Symbiotics

Hugo E. Schwarz.

Cerro Tololo Inter-American Observatory, NAOA/AURA.

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Asymmetries in PNe.• Most field stars are unpolarized.• 3/4 of AGB stars is polarized. (Johnson, Jones 1991, AJ 101, 1735)

• Most PNe are not circular, many are extreme.• Some ~50% have binaries. • Extreme global asymmetries due to binaries.• Point symmetry due to precession.• Links to symbiotics & symbiotic nebulae.• Different properties of bipolar PNe.

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Bipolar properties• Scale height 130pc v. 260pc

• Nearer pure circular Galactic rotation• Hotter central stars 145kK v. 75kK

• He, N, & Ne are overabundant• Vexp higher 150km/s v.15km/s

• Large size 0.76pc v. 0.1pc

• More massive progenitors >1.5M

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Bipolars-Symbiotics-PNe• 40% of D&D’ symbiotics have nebulae.

• Post-PN nebulae: BI Crucis (3 nebulae).

• AS201 fossil PN, ionized nebula, G star.

• 5/14 symbiotic nebulae are bipolar.

• Binaries explain both phenomena.

• M2-9 needs faint, hot star binary.

• Blue-red shifts in the same lobe (IC4234).

• Point symmetry explained by precession.

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Name Type Size[“] Shape Vexp [km s-1]

AG Peg (?) S 8 irregular  

AS 201 yellow 13 elliptical 16

BI Cru D 150 bipolar+jet up to 280

CH Cyg S 32 jet+irregular >65 (>>?)

H 1-36 D 0.9-1.5    

H 2-2 (?) S 1.4    

HBV 475 S 0.4 irregular  

He 2-104 D 95 2 bipolar+jet 6 to 240

He 2-147 D 5 ring 100

HM Sge D 30 irregular >65

R Aqr D 120 bipolar+jet 55 to 500

RX Pup D 4 bipolar? >80

V417 Cen yellow 100 bipolar 10:

V1016 Cyg D 20 elliptical >30

Corradi et al. 1999 A&A 343, 841

Symbiotics with optical nebulae

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Symbiotic nebulae

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Symbiotic nebulae (SyNe)• Nearly 4 times more are bipolar cf. PNe.• Average Vexp is 140km/s as for BPNe.• Average z = 133pc as for BPNe.• For BSyNe z = 98pc (only 5 objects)• Most have [NII] as strongest lines.

• SO SYMBIOTIC NEBULAE SHARE MANY PROPERTIES WITH BPNe

& are binaries…

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Post-PN-NebulaSchwarz & Corradi 1992, AA 265, 37Model of Morris 1987, PASP, 95, 1115

BI Cru

Vexp = 280 km/s

VH = 3000 km/sCentral reversal2 nebulae: H/L exc.D = 1.8kpcS = 1.3pc, Age = 3kaL = 4300L

High excitation nebula(unresolved)

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M2-9: PN & symbioticSize = 115“, outer lobes point symmetric,

Inner nebula has plane symmetry.

Outer lobes reflecting dust

L=553L; d=640pc; age=1200yrs; s=0.37pc

HST image

Both plane and point symmetries due to binary orbit phenomena: rotating central dustclouds and precession?

“Symbiotic“ emission lines, prob. disk.

[OIII] line, so hot, subluminous *:

WD+MS or RG are present = binary.

Schwarz et al. 1997 AA 319, 267Doyle et al. 2000 AJ 119, 1339

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Sa2-237 Vexp=308km/sS = 0.37 pc 34”L = 340 L

D = 2.1kpcAge = 624 a

As M2-9: [OIII] present, low L,so WD, so binary. Study CS….

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AS201: P-PN-N in the making?

AS 201

Schwarz 1991 A&A 243, 469

Low excitation nebula,old, faint, extended.High excitation inner nebula.Symbiotic & PN.

When CS forms disk…get an object like BI Cru?

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A79, He2-428, M1-91Rodriguez, Corradi, Mampaso 2001 AA 377, 1042

Strong mass loss/exchange in unresolved cores.CaII triplet in emission, high , excretion disk.Cont. and absorption lines indicate hot star with cool companion.Equatorial rings and polar lobes.

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Precession, point symmetryRed and blue shifts on the same side of the object.Only if LoS or Sky cut precession cone.

Observed in IC4634

IC4634Long slit spectrum.

SPATIAL

VELOCITY

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Random distribution on the sky.

Number of objects at inclination, i, sin(i). For a precession cone with opening angle 2 , only those objects with 0 < i or /2 < i /2 where 0 < /4 will show red and blue shifts on the same side of the central object (RB effect). Integrating between 0 & and /2 & /2 we get: f( ) = 1 cos( ) + sin( ) which is near linear with inclination angle. So for a typical opening angle of 30o the fraction of objects that show the RB effect is about 30%.

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Strong links: PNe-Symbiotics-Binaries

• All (extreme) bipolars are binaries

• All symbiotics are binaries

• Evolutionary stage is important (P-PN-N)

• Some equatorial density enhancement

• Orientation effects should occur

• Model these, cf. observations.

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Inclination effects.High inclination objects hide the central

object behind their equatorial mass concentration, and therefore show more FIR radiation; low inclination

objects show the central object and this increases the fraction of visible & NIR

light we see.

So…Computing the UBV (VIS), JHK (NIR), & IRAS (FIR)

relative fraction of the total flux, we should see an effect.

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Crude model of inclined nebulae

• Donut (BB) around point source (BB)

• Stellar flux captured is converted to IR

• Random i orientation in space

• Plot fractions of BVR, JHK, & IRAS (i)

• Cf. observations for various BBs:

• Donut 600K; Star 10, 20, 40, 80kK

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Observed sample

• ~30 objects, partial SEDs, some distances

• Estimate inclinations from images (3x)

• Use BVR, JHK, IRAS “bands” relative to sum of these bands.

• Do same for simulation data, compare.

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FIR

VIS & NIR

Observed sample

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Random sample• Generate random binaries.

• i random with sin(i) histogram

• Donut dust distribution, 15% stellar

• Plot same parameters as observed data.

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Random sample = FIR = NIR = VIS

1000WD200RG200K dust

1000WD200RG400K dust

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LUMINOSITIES

Another predicted effect is that high inclination objects should have lower apparent luminosities due to the fact that only the equatorial “donut” is seen, while for low

inclination the central object plus donut is observed giving an apparent over-luminosity. Over all angles, averaging

makes sure that no energy conservation laws are broken; Ltot = n.Lave

Distances being uncertain for all but a few objects, we have:

High inclination (>45) 

Sa2-237 I=70 2.1kpc 340 LoM2-9 I=75 0.64kpc 553 LoHe2-104 I=50 1kpc 205 Lo

He2-111 I=70 2.8kpc 440 LoM1-16 I=70 1.8kpc 194 Lo

  346 Lo

Low inclination (<45) 

R Aqr I=20 0.2kpc 2800 Lo BI Cru I=40 1.8kpc 4300 Lo   3550

Lo 

There is some indication of lower luminosities being associated with high inclinations.

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Luminosity v. inclinationfrom the same simulation.

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Note that the number of objects increases with inclination as sin(i); this is expected just from the statistics of randomly orientated

objects, and is strengthened by observational selection of bipolars by their morphology. Objects that are (near) pole-on are not recognized

as bipolars and are therefore selected against.We have:

  

0 - 30 3 objects31- 60 11 objects61- 90 14 objects

   

This is the expected behavior and is of the right order but there are too few objects to make this harder.

Statistics

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Conclusions

• PNe, SyNe are linked.

• PNe, SyNe are often indistinguishable

• Asymmetrical nebulae ( nearly always) have binaries.

• Orientation effects are important

in interpreting & constraining

observations.